The Last Banquet, a novel set in the run-up to the French Revolution, which literary readers decided was literary and fantasy readers suspected was really fantasy, earned me a handful of very pretty foreign editions, a shortlisting for the 2014 Bad Sex Award, and a social media string about what kind of food went with sex.

(The obvious answer is any kind.)

My publisher and agent assured me the shortlisting was a huge honour, involving only books the literary establishment took seriously and should be embraced. I wasn't sure I believed them.

Asked for a response by the papers, I said people who thought sex and food didn't go together deserved neither. The broadsheets duly printed the quote. Instead of going to the awards I went to Stockholm to sulk in a cinema converted to a hotel by Benny from Abba and hang out in the café Stieg Larsson used to write The Girl with the Dragon Tattoo. For me, the passage that earned me the shortlisting wasn't even about sex, it was about a man's regret for what he'd lost and would never get back.

I didn't win and was grateful.

The episode did, however, make me question why I instinctively included sex when writing fiction. And ask myself what I'd lose by writing asexual characters, fading out at the bedroom door, or writing people who fucked off-stage and referenced it later. The answer was that I'd lose more than I was prepared to lose for an easy life. For me, who, when, why, and how the cast fuck helps characterisation and occasionally plotting.

There are unquestionably novels out there, particularly in genre, where the cast never seem to sleep, go to the lavatory, or eat except on formal occasions or at feasts. For me, and the characters I write, how well they sleep, what they eat, and who they have sex with (and why) is an integral part of defining them as human.

The bad sex award wasn't the first time I'd been forced to think about how what I wrote might be taken. Shortly after reMix came out in 1999—my third novel, the tale of Fixx, a burned-out, literally legless DJ and his quest to get back LizAlec Fabio before her mother has him killed—I received a worried letter from a reader in her teens. There's a slightly unhinged scene towards the end of the book, which, if I remember rightly, mentions shit, spit, blood, and semen in passing. The young woman wanted to know if that was what she should expect and how sex was meant to be. . . . 

I decided on the spot that I shouldn't be trusted to write YA.

(And a few years later, when an editor setting up a list asked if I'd like to write for her, I turned the offer down and gave that letter as my reason.)

I wrote back to say that's just how sex was for that character with that other character in that particular scene in that particular book. I said that she'd notice one of the characters was a tired and overworked bar owner, and the other a crystal meth addict with a bad conscience, what was left of it. She absolutely shouldn't read anything into their coupling except that two very damaged people found comfort.

And that's the thing. The main character in The Last Banquet, with his search for enlightenment through taste, texture, and a passion for taxonomy, is a long way from Fixx, and not just in the layering of the later book's narrative. The Last Banquet's descriptions of sex are intentionally lyrical; the writing style of the earlier book is intended to be as transparent as a film script, while the later novel tries to imitate a French novel in translation.

There was a time, pre-internet, when sex was put into fiction simply as a selling tool. I'm always reminded of the (possibly apocryphal) story of Peter Benchley being told by his editor in the 1970s to include raunchier sex scenes in Jaws. He was certainly told to remove a scene on the basis that there was no room for "wholesome marital sex in this kind of book. . . . " And as Harold Robbins said in an interview with Advocate in the mid '90s, "Years ago, sex was very big for readers. Today, it's violence and murder."

The me who wrote reMix is a long way from the me who wrote The Last Banquet. And the markets I wrote them for are very different. Age changes us. At best, I can hope to gain in experience and technique what I've lost in drive and fire. I don't get up at 6.30 to write two thousand words before breakfast these days because I don't have the stamina. I'm grateful if I manage two thousand new words by the time I fall into bed. In the same way, what I intended as an almost forensic coldness in the depiction of violence and sex in my early books now feels dated and inappropriate. I know that more can be suggested. That less needs to be said. That what is described in detail needs to resonate like a bell beyond its scene into the rest of the book.

The level of frankness and depth of detail I can use depends on the genre, on the particular editor, and quite possibly how on I see the characters in that particular book. I wince at some of the scenes from my earliest novels without knowing if the wincing is age related, and whether if I was that age now I'd still write those scenes as I wrote them then. (Of course, when writing non-humans I'm free to make up my own answers or ignore the questions.)

Writing sex is easy in my opinion.

Writing it well is harder.

Writing it so it advances the plot or delineates character harder still. Sometimes much harder. Sometimes bloody close to impossible. And to fail is to invite brickbats and name-calling. Not that surprising, given how deeply we've embedded the act in our emotional, political, and theological frameworks. (Obscenity laws still exist to jail people who write sex in a way the authorities didn't/don't like.)

I come from a family privileged enough to be fairly open in its sexuality, and have learned to not underestimate the luxury that gives me, both in life and when it comes to writing. It took a conversation in a restaurant about a couple of lesbian aunts of mine and a gay great uncle to realise from the sudden stillness of the person opposite that many don't have that privilege.

For me, the sex I write doesn't have to be between men and women, it doesn't have to be within a monogamous framework; it can be the heroine and her best friend, the hero and a guy he meets in a bar, the characters can be hetero, gay, bi, or entirely fluid. . . . 

But it has to say something.

What it says for me has changed from book to book and I want to look at few examples and try to work out what I thought I was saying.

Not knowing I was in the room, I once heard a speaker at a convention say I'd written one of the most erotic scenes that she'd read in genre. I was hugely flattered (and felt that she had an impressively clear eye). What interested me was that the scene she referenced had no penetration, little foreplay, very few, if any, clothes removed, and what the major character was searching for inside herself as she came had little to do with the hero and everything to do with her broken family and unhappy childhood. The scene existed to remind the reader how lonely she'd been and to suggest that happiness is some form, however fractured, was a possibility.

There's no doubt that different publishers have different expectations and acceptances of frankness. And to say the UK is more accepting than the US is a simplification. There's one well-known UK editor famous for demanding her writers abandon their characters at the bedroom door whether the writers want to or not. Against that, US East Coast editors have a habit of producing the easily upset and biblically inclined Midwestern reader like a rabbit from a hat as a veto on certain "otherwise entirely acceptable" scenes.

Politics is more tricky still.

I remember a US copy editor emailing to say she'd be changing all the references in Pashazade from global warming to climate change and that wasn't a problem, was it? Mind you, a friend was told she could remove all references to abortion or lose her Wal-Mart sales.

(She chose to lose the sales.)

In the earliest books, reMix (1999) and redRobe (2000) in particular, the act was largely mechanical, as fast paced as the action and of a part with it. Little distinction was made between body parts, the parts of gun, and the use of both. Somewhere unachievable in the back of my head was the aim of meshing a Ballardian coldness with the nastiness of Noir and lacquering the result with a cyberpunk surface gloss.

The Arabesk novels (Pashazade [2001], Effendi [2002], Felaheen [2003]), set in an alternate 21st-century North Africa, and all featuring the same half-Berber detective Ashraf Bey, were my attempt to step back from that, to slow down the narrative by using more complex and longer sentences, and to lead on character rather than plot. The relationship between the Ashraf Bey and Zara, the Egyptian heiress he's been sent to El Iskandryia to marry, is complicated by Zara's understandable objection to the marriage, by her having been "circumcised" as a child, and by Raf's previously most intense relationship being a love/hate one with a young male gangster. (Most major characters in my novels are bi. I've been told it's unfashionable, but I still tend to believe that most people are somewhere on the scale. I have both lesbian and gay characters, of course, and purely heterosexual ones, but mostly. . . . )

There's a scene where Zara kneels to perform oral sex, something she previously refused to do because it involved kneeling before a man, and the reader doesn't know (and I didn't know when I wrote it) if she does it because she loves Raf and finally decides to compromise or because she needs him to help protect her father. The point is that Raf doesn't know either and neither ever mentions it again.

(There's a risk, I believe, in a man writing a woman. Just as there is in a woman writing a man; or someone bi writing the sexual response of someone straight or gay and vice versa. That's before we get into the more general minefield of someone old writing someone young, someone white writing someone of colour, or anyone writing across religions and cultures and class. All we can do is do our best and take criticism. If I ever stopped to consider fully the arrogance inherent in writing novels I'd never write at all. Nor, I suspect, would anyone else…)

By the time I wrote 9tail Fox (2005), I knew sex was more about what the characters wanted emotionally than needed physically. The scene that matters to me in that book is a goodbye.

End of the World Blues (2006), set in Tokyo and featuring a British sniper on the run from the Iraqi war, is still one of my favourites, but proved more complicated still. It was my attempt to write a Murakami novel, and when the book opens, the marriage between Kit and Yoshi, his Japanese wife, is so hollow that sex has been stripped of emotion, and reduced to a polite formality if it happens at all. The sparseness of the early prose is intended to mirror that.

Kit finds his comfort with the wife of a Japanese gangster; while Yoshi, already famous as a potter, simply needs the mental release being bound brings to create bowls fragile enough to reflect her emptiness. Kit's function in the marriage is to bind Yoshi when she declares it necessary. The complicated knots of Edo rope bondage that Kit learns to use mirror those of the sky ropes in Nawa-no-ukiyo, the end of time floating rope world, which is itself a play on Hokusai's floating world. I needed help from Japanese friends both to explain the aesthetics of Edo rope bondage, and to translate the sections of Yamamoto Tsunetomo's Hagakure that Kit quotes in the final scene.

It's a book almost entirely about the things that bind us.

And endings.

To work at any meaningful level sex in my fiction needs to be more than will he or won't he? Or even should she or shouldn't she? It has to say something in itself about the character. My main memory of the Assassini books (The Fallen Blade [2011], The Outcast Blade [2012], The Exiled Blade [2013]), set in 15th-century Venice and dealing with the first vampire in Europe, is finding a marginal note in the US edits that read simply, this isn't very nice.

Lady Giulietta is in the aftermath of a brutal sea battle and has just lost a husband she adored (for all he was gay and didn't love her, at least not in that way). Her life is in ruins, her happiness is rubble around her feet. What the scene said for me was not that she was being unfaithful to his memory, not that she was in some way two-timing a dead man, it said she was stricken with grief. Being nice is the last thing on her mind in that scene. It should, to be honest, be the last thing on the reader's mind too.

The sexual relationships in these books are as tangled as the politics of Venice itself. But for me the one that resonates is the love affair in the second book between Rosalyn and Lady Eleanor, teenagers who find unexpected happiness in each other. I was trying to capture the sweetness and despair of a true first love.

What I wanted was a suggestion of an intense physical relationship without a description of the mechanics, which I'd have felt impelled to include even ten years earlier. I didn't consciously close the bedroom door on Rosalyn and Lady Eleanor, but the moment the scene finished and the rest of me caught up with my unconscious, I knew that was where it was meant to end.

At the end of the third book the boy gets the boy and I was pleased with that, too. Sadly, we had to lose the epilogue where we cut to them a hundred years later as they bickered their way across Europe from adventure to adventure like an old married couple. I did, however, get a very sweet letter from an elderly American woman saying she was delighted the hero finally had a friend.

At its most relevant, sex in fiction needs to be talking about something else and that's what I was trying for in the following, the paragraph that got me nominated for the Bad Sex Award:

By then I'd begun unbuttoning her blouse and didn't stop until it was open to the waist and her breasts exposed. Gently, I opened her knees, but only so I could kneel between them and put my mouth to her breast and suck. In my mouth her nipple turned from strawberry to deep raspberry but the taste I wanted was missing. I had sweat, and what had to be soap from washing her dress or herself. Reaching behind me, I found brie and broke off a fragment sucking her nipple through it. She tasted almost as she had the day I took the drop of her milk on my finger. . . 

Jean Marie's lifelong search for the perfect taste is actually a quest for the impossible. The fact he knows that doesn't stop him trying. And he's astute enough to know his attempts to codify food into a periodic table of taste are at odds with his need as an artist to extract an emotional response from the world around him.

He's lucky enough to live in the age of the Encyclopaedists, in the Age of Enlightenment, when science and art are still, just about, in bed with each other. But the gap between them is already widening and the more of the world Europe "discovers," the harder it becomes for one man to codify. Whether the relationship between food and sex in The Last Banquet is able to carry the weight of the metaphor is down to the reader.

I'd like to end with a quote from Stoppard taken from his 1982 play The Real Thing. It says everything better than I can.

We share our vivacity, grief, sulks, anger, joy . . . we hand it out to anybody who happens to be standing around, to friends and family with a momentary sense of indecency perhaps, to strangers without hesitation. Our lovers share us with the passing trade. But in pairs we insist that we give ourselves to each other. What selves? What's left? What else is there that hasn't been dealt out like a deck of cards?

Carnal knowledge.

Personal, final, uncompromised.